import java.util.LinkedList;
import java.util.Queue;

public class Main {
    public static void main(String[] args) {
        Queue<Integer> queue = new LinkedList<>();
        System.out.println(queue.isEmpty());
        queue.offer(11);//入队列
        queue.offer(22);
        queue.offer(33);
        queue.offer(44);
        queue.offer(55);
        System.out.println(queue);
        System.out.println(queue.size());//获取有效元素的个数
        System.out.println(queue.isEmpty());//检查队列是否为空
        System.out.println(queue.peek());//获取头元素
        System.out.println(queue.poll());//出队列
        System.out.println(queue.poll());
    }
}
